Mysterious condition! Please assist!

Please assist with any ideas for diagnosis.
I have a family member that has been in and out of hospital for about 3 years now.

A couple of years ago she went to hospital thinking she has mumps since one of the children had it.

Then something went horribly wrong and she ended up in ICU in a coma with her organs failing and her body swelling, she almost died.

From there NO DOCTOR has been able to diagnose what happened or confirm if she had mumps in the first place, at one point they speculated that she might have caught a bug in the hospital but could not confirm it, they have no idea what it was/is to this day.

Symptoms:
- Hypertension 250/156, no drug has been able to bring it down.
- Low levels of potassium (hypokalemia?), the potassium disappears and they can’t find where it is going, she receives potassium daily, they struggle to get the level above 2.
- Heart Failure, I assume from the hypertension?
- Kidney failure, a specialist has burnt some nerves to try and postpone her kidneys from completely failing, biopsy was done, didn’t find anything
- MRI scans done, nothing
- Numerous blood tests have been and are still being done, without any real answers
- Urine tests have been and are being done, no real answers
- Pancreatitis was ruled out
They fear that without a proper diagnosis and the correct treatment that she might not make to the end of this year. I assume with all the tests that has been done the diagnosis will probably not be something obvious but perhaps a series of things affecting one another. Perhaps someone might identify something that has been overlooked or guide us toward the right people that can help us.
Please assist us in any way to diagnose this or perhaps refer me to a specialist or research facility or institute that will be willing to take her case.
Thank you.